Final answer:
The current IR in an RC parallel circuit with a total voltage of 240 V and a resistance of 40 Ω is 6 amps, calculated using Ohm's Law by dividing the total voltage by the resistance.
Step-by-step explanation:
To calculate the current IR in an RC parallel circuit with the given values of ET (total voltage) = 240 V, R (resistance) = 40 Ω, and XC (capacitive reactance) = 30 Ω, we use Ohm's Law. Ohm's Law states that the current through a resistor in an electrical circuit is directly proportional to the voltage across it and inversely proportional to the resistance. In this case, because we're dealing with a parallel circuit component, the voltage across the resistor is the same as the total voltage (ET).
To find IR, we simply divide the total voltage by the resistance:
IR = ET / R = 240 V / 40 Ω = 6 A
The current IR through the resistor is therefore 6 amps.